After nearly two years of stark divisions over the war in Gaza and support for Israel, Democrats are now finding themselves at odds over US policy toward Iran as progressives demand unified opposition to President Donald Trump’s consideration of a strike against Tehran’s nuclear program while party leaders tread more cautiously. US leaders of all stripes have found common ground for two decades on the position that Iran cannot be allowed to obtain a nuclear weapon. The longtime US foe has supported groups that have killed Americans across the Mideast and threatens to destroy Israel.